Code Examples

Real-world examples demonstrating Sentra’s capabilities.

---

Security Tools

Port Scanner

// Simple port scanner
fn scan_host(host, start_port, end_port) {
    log("Scanning " + host + " ports " + str(start_port) + "-" + str(end_port))
    
    let results = port_scan(host, start_port, end_port, "TCP")
    let open_ports = []
    
    for (let port in results) {
        if (port["state"] == "open") {
            push(open_ports, port["port"])
            log("  Port " + str(port["port"]) + " OPEN - " + port["service"])
        }
    }
    
    return open_ports
}

// Usage
let ports = scan_host("127.0.0.1", 20, 100)
log("Found " + str(len(ports)) + " open ports")

Web Vulnerability Scanner

// Check for common web vulnerabilities
fn scan_website(url) {
    log("Scanning " + url)
    let issues = []
    
    // Check security headers
    let response = http_get(url)
    let headers = response["headers"]
    
    if (!headers["X-Frame-Options"]) {
        push(issues, "Missing X-Frame-Options header")
    }
    
    if (!headers["Content-Security-Policy"]) {
        push(issues, "Missing CSP header")
    }
    
    if (len(issues) > 0) {
        log("Security issues found:")
        for (let issue in issues) {
            log("  - " + issue)
        }
    } else {
        log("No issues found")
    }
    
    return issues
}

scan_website("https://example.com")

---

Network Programming

HTTP Server

// Create a REST API server
let server = http_server_create("127.0.0.1", 8080)

// Health check endpoint
http_server_route(server["id"], "GET", "/health", fn(req) {
    return http_response(200, '{"status": "healthy"}', {
        "Content-Type": "application/json"
    })
})

// Data endpoint
http_server_route(server["id"], "POST", "/data", fn(req) {
    log("Received data: " + req["body"])
    return http_response(200, '{"received": true}', {
        "Content-Type": "application/json"
    })
})

http_server_start(server["id"])
log("Server running at http://127.0.0.1:8080")

// Keep server running
while (true) {
    sleep(1000)
}

WebSocket Chat Server

// Simple WebSocket chat server
let server = ws_listen("127.0.0.1", 8765)
log("WebSocket server running on ws://127.0.0.1:8765")

let clients = {}

while (true) {
    // Accept new connections
    let client = ws_server_accept(server["id"], 1)
    if (client) {
        clients[client["id"]] = client
        ws_server_send_to(server["id"], client["id"], "Welcome to chat!")
        log("Client connected: " + client["id"])
    }
    
    // Handle messages
    for (let id in clients) {
        let msg = ws_server_receive_from(server["id"], id)
        if (msg) {
            log("Broadcasting: " + msg)
            ws_server_broadcast(server["id"], "[User]: " + msg)
        }
    }
    
    sleep(100)
}

---

Data Processing

Log Analyzer

// Analyze security logs
fn analyze_logs(filename) {
    if (!file_exists(filename)) {
        log("File not found: " + filename)
        return
    }
    
    let content = file_read(filename)
    let lines = split(content, "\n")
    let stats = {
        "total": 0,
        "errors": 0,
        "warnings": 0,
        "failed_logins": 0
    }
    
    for (let line in lines) {
        stats["total"] = stats["total"] + 1
        
        if (contains(line, "ERROR")) {
            stats["errors"] = stats["errors"] + 1
        }
        if (contains(line, "WARNING")) {
            stats["warnings"] = stats["warnings"] + 1
        }
        if (contains(line, "Failed login")) {
            stats["failed_logins"] = stats["failed_logins"] + 1
        }
    }
    
    log("Log Analysis Results:")
    log("  Total lines: " + str(stats["total"]))
    log("  Errors: " + str(stats["errors"]))
    log("  Warnings: " + str(stats["warnings"]))
    log("  Failed logins: " + str(stats["failed_logins"]))
    
    return stats
}

analyze_logs("/var/log/auth.log")

---

Algorithms

Sentra includes 40+ classic algorithm implementations demonstrating the language’s capabilities.

Two Sum (Hash Table)

fn twoSum(nums, target) {
    let seen = {}
    for (let i in range(0, len(nums))) {
        let complement = target - nums[i]
        if (seen[str(complement)] != nil) {
            return [seen[str(complement)], i]
        }
        seen[str(nums[i])] = i
    }
    return []
}

log(twoSum([2, 7, 11, 15], 9))  // [0, 1]

Quick Sort

fn quickSort(arr, low, high) {
    if (low < high) {
        let pivot = arr[high]
        let i = low - 1

        for (let j in range(low, high)) {
            if (arr[j] <= pivot) {
                i = i + 1
                let temp = arr[i]
                arr[i] = arr[j]
                arr[j] = temp
            }
        }

        let temp = arr[i + 1]
        arr[i + 1] = arr[high]
        arr[high] = temp
        let pi = i + 1

        quickSort(arr, low, pi - 1)
        quickSort(arr, pi + 1, high)
    }
    return arr
}

let arr = [64, 34, 25, 12, 22, 11, 90]
log(quickSort(arr, 0, len(arr) - 1))  // [11, 12, 22, 25, 34, 64, 90]

Dynamic Programming (Coin Change)

fn coinChange(coins, amount) {
    let dp = [amount + 1]
    for (let i in range(0, amount + 1)) {
        dp[i] = amount + 1
    }
    dp[0] = 0

    for (let i in range(1, amount + 1)) {
        for (let coin in coins) {
            if (coin <= i && dp[i - coin] + 1 < dp[i]) {
                dp[i] = dp[i - coin] + 1
            }
        }
    }

    if (dp[amount] > amount) {
        return -1
    }
    return dp[amount]
}

log(coinChange([1, 2, 5], 11))  // 3 (5+5+1)

Algorithm Categories

The full leetcode.sn includes:

Category	Algorithms
Hash Tables	Two Sum, Contains Duplicate, Single Number
Two Pointers	Container With Most Water, Trapping Rain Water
Binary Search	Search Insert, Sqrt(x), Find Min in Rotated Array
Dynamic Programming	Climbing Stairs, House Robber, Coin Change, LIS
Greedy	Jump Game, Best Time to Buy/Sell Stock
Arrays	Move Zeroes, Rotate Array, Product Except Self
Math	Palindrome, Happy Number, Power of Two, GCD
Sorting	Quick Sort, Merge Sorted Arrays

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More Examples

Find comprehensive examples in the GitHub repository:

• Security: Vulnerability scanners, penetration testing tools
• Networking: TCP/UDP servers, HTTP clients, WebSocket applications
• Algorithms: 40+ LeetCode problems with solutions
• System: File operations, process management, OS interaction

View All Examples on GitHub →